And I'm Melissa Block. Team Great Britain is enjoying a stellar run at the London games. The Olympic host team has already won more medals than any year since 1908 when it also hosted the summer games, 48 medals so far with four days to go. And, turns out, this is a pattern. The host country does rake in the medals. China in 2008, Greece in '04, Australia in 2000. All of them hit all-time highs in the medal count.

Nigel Balmer has looked into why that is. He's a researcher at University College, London. Welcome to the program.

NIGEL BALMER: Thank you.

BLOCK: And let's talk about what you found. When you look at the medal counts, how dramatic a bump do you see with the host countries?

BALMER: Well, very dramatic. If I start you off with possibly the most dramatic example, if we go back to 1904, Great Britain won two medals in America. 1908, when they were hosting it in London, they won 146.

BLOCK: That's a big jump.

BALMER: So that's possibly the most dramatic example.

BLOCK: What about more recently? What do you find?

BALMER: Well, more recently, we've seen some not quite as dramatic examples, but Spain, in 1988, won four medals. When they hosted it four years later, they won 22. Australia in Melbourne, they won 11 medals four years earlier, then they won 35. And, of course, China went from 63 to 100 medals, which you already mentioned. On the other end of it, I'm afraid to say, well, we have USA and Atlanta, so in 1992 in Barcelona, they won 108 medals. In Atlanta, sadly, it went down to 101 medals, so it's not always the case.

Generally, we see some pretty spectacular home advantage, but there are examples like that.

BLOCK: So the U.S. bucking the trend slightly there. One of the factors that you found out here that determines this bump is money. Big investment in the athletes and putting on a good show for the home games.

BALMER: Yes. Well, there's a number of factors that might have some impact, so you know, there's the amount of preparation you put in, the amount of money you spend. There's the number of athletes, so you know, home games, you generally can enter more athletes because it's cheaper to do so and that's going to have some impact.

Beyond that, factors that we tend to think of as explaining home advantage are travel factors, so the fact that some teams have to travel further, they might be more fatigued. Familiarity, so the fact that you might be more familiar with home venues. You could imagine that having more of an impact in things, for example, like BMX or sailing, where you have some very specific home conditions.

BLOCK: Yeah, sure.

BALMER: And then the third factor, which is where I've done most of my work, is crowd factor. So the idea of whether the support of a vociferous home crowd can actually increase your chances of winning.

BLOCK: Yeah. That's an interesting one right there. I mean, have you found that that does bear itself out, that a raucous British-loving crowd there in London will help a British athlete? Say Andy Murray, the final in men's tennis. Right? They loved him. They were crazy for him.

BALMER: Well, interestingly, I would say that home crowds have less chance of impacting Andy Murray than it would have other athletes. This goes back to some research I did - well, it's about 10 years ago now. One mechanism we propose to explain crowd factors is that strong home support influences officials to make more decisions in favor of the home side, so you're likely to see increased home advantage in events that are subjectively judged. So where the officials decide the outcome, gymnastics, boxing and, of course, everyone's favorite, dressage, you're also likely to see some home advantage in team games where officials aren't deciding the outcome, but they are making some key decisions, so we'd be thinking of things like soccer or hockey.

BLOCK: So you're saying, though, that the roar of the crowd wouldn't necessarily improve an athlete's performance, just having that huge bellow of support behind them?

BALMER: Well, I would suspect, in many cases, it could have a detrimental effect, but certainly, when we did this study, once we'd controlled the number of athletes that home nations entered, home advantage almost disappeared from events like athletics and weightlifting, for example, and we still see quite substantial home advantage in subjectively-judged events like gymnastics.

So the message for the crowd's clear. If you're going to see the boxing, you should really cheer as loud as possible.

BLOCK: Nigel Balmer, thanks so much for talking with us.

BALMER: No problem.

BLOCK: And enjoy the rest of the games.

BALMER: I will do.

BLOCK: That's Nigel Balmer talking about the host country advantage in the Summer Olympics. He's a researcher at University College, London. And here's his prediction for the total number of medals the team Great Britain will win in this Olympics: 63. Transcript provided by NPR, Copyright NPR.